User Guide WUG-10003-02

OMNIC2, F2, R2 and T2 Meters

User GuideWUG-10003-02

Revision History

Copyright

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Sensus8601 Six Forks RoadSuite 700Raleigh, NC 276151-800-638-3748www.sensus.com

Document: OMNI User GuideDocument Number: WUG-10003-02

Rev No. Date Description

Rev 1 30-SEP-2009 Initial Release

Rev 2 15-MAR-2016 Added revised drawings, minor additions and corrections

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Contents

Introduction5 Specifications

OMNI Installation6 Required Tools6 Installation Instructions

Signal Connections9 Description9 Features9 Application9 Electrical Connections

Measuring Chamber13 Tools Required14 Remove the Measuring Chamber15 Disassemble the Measuring Chamber17 Exchange the Measuring Insert

Introduction 1The OMNI family of meters are a technologically advanced set of water meters with no restrictions as to sustained flow rates within its continuous operating range. OMNI meters feature Floating Ball Technology (FBT), which allows the measuring element to operate virtually without friction or wear.

Each OMNI meter consists of two basic assemblies: the maincase and the measuring chamber. The measuring chamber assembly includes the “floating ball” impeller and an all electronic programmable register. The OMNI electronic register is a hermetically sealed register with an electronic pickup containing no mechanical gearing.

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Category Specification

Input Power 12-24 VDC ± 10%

Output Signal Open Collector—Digital Signal

Wiring Red = + Power Supply VoltageGreen = Pulse, Switching to GroundBlack = Ground (- Power Supply Voltage)

Contact Closure Duration 30ms Minimum (at 16Hz Output)a

a. With lower frequencies, the duration is longer. The duty cycle is roughly 40-60% closed/60-40% open. It depends on the frequency, and is not as important as the contact timing.

Contact Open Duration 30ms Minimum (at 16 Hz Output)b

b. With lower frequencies, the duration is longer. The duty cycle is roughly 60-40% closed/40-60% open. It depends on the frequency, and is not as important as the contact timing

Duty Cycle Approx. 50/50 ± 20% at normal flow rates

Pull-up Resistor (when required)

6000 Ohms

Pulse Cable Length 25 ft. at meter

Pulse Cable Diameter 3.6 mm

Insulation Colors Red—12 to 24 VDC (Supply)Green—Pulse, switching to GNDBlack—GND

Maximum Cable Run - Meter to Instrument

1000 ft. without a repeater

Lightning Protection Built-in lightning protection. Keep in mind that additional lightning arrestors may be needed when long cables are used to connect the register to devices which are not installed in the same building as the register. The flash of lightning is not compatible with the standards and can have greater energy than any test can simulate.

Specifications

Introduction 5

OMNI Installation 2Required Tools• Correct tools for the corresponding size of bolts that are used. In the case of the

R2, 5/8” bolts are used for the 1-1/2” R2 and 3/4” bolts are used for the 2” R2.• Hoisting devices may be required, depending on the weight of the meter and the

installation conditions.

Installation InstructionsTo ensure valid registration, proper performance, and meter longevity, the following factors should be considered when installing Sensus OMNI Meters.

1. When installing Sensus OMNI Meter with the strainer, a minimum of 2-½ pipe diameters of straight run of pipe or equivalent full open components is required upstream and downstream of the meter or strainer flanges. Full open flow components may consist of: straight pipe, full open gate valves, bypass tees, all of the same nominal size as the meter, and concentric reducers (1 nominal pipe size reduction only).

2. Gate valves located immediately upstream or downstream are acceptable, provided they are fully open during meter service and are not used to throttle flow rates through the meter.

3. Install non-concentric reducers, check valves, back flow preventers, PRV (pressure reducing valves), throttling devices, altitude valves no closer than 4 pipe diameters downstream of the meter. Always avoid placing any of these devices upstream of any meter since the placement will put the meter in a low pressure zone thus possibly causing inconsistent accuracy and reduced longevity.

4. Accuracy levels may be determined by comparison accuracy testing either by using a Sensus Portable Large Meter Tester, by removing the suspect meter and testing it on a calibrated test bench or returning the suspect measuring chamber or complete meter to Sensus Metering for a certified accuracy test

NOTE: High flow meter applications or near to open air discharge must maintain a minimum of 25 psi downstream pressure to assure accuracy and meter longevity.

OMNI meters can be installed vertically or rotated on the bolt pattern in any orientation. Contact Sensus with any questions.

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2 Dia. MinimumStraight Pipe

Recommended

Bypass Tee

Full-OpenGate Valve

Sensus OMNI Meter(Shown)

2 Dia. MinimumStraight Pipe

Recommended

Bypass Tee

Test Outletw/LockingBall Valve

Smith-Blair Coupling

Bypass Valve ClosedDuring Meter Use

UpstreamDownstream

Smith-Blair Flange CouplingAdaptor w/Anchor Studs(Optional Flexibility)

Flow

1/2 1/2

5. No mechanical stresses should be exerted on the meter when installed in the pipeline. The pipeline flanges must align with the meter flanges, the distance between the flanges must match the meter body length, and the weight of the meter must be supported evenly. Mis-alignment stresses can cause the meter body or flanges to crack; thus, when the pipeline is under pressure, flooding can occur.

6. The meter must not be subjected to pressures higher than the pressure rating printed on the data sheet. Too high pressure can cause leaks or burst the meter body.

7. Gaskets must not protrude into the pipeline or be misaligned.

8. The pipeline must be thoroughly flushed before installing the meter to prevent damage from debris.

9. The flow direction of the meter (arrow on the meter body) must correspond with the flow direction in the pipeline.

10. After installation of the meter, the pipeline must be filled with water very slowly to prevent the meter being damaged by surges. Filling the pipe too rapidly can cause air/water surges, which can destroy the meter insert.

11. The installation site should be chosen to prevent air bubbles collecting in the meter and the pipeline must always be completely filled with water. Installation of a meter at the highest point in a pipeline must be avoided.

OMNI Installation 7

12. The manufacturer’s normal flow must not be exceeded for extended periods. Applications with questionable water quality should be addressed with Sensus Engineering before meter installations.

13. The meter should be protected from stones, sand, and fibrous material.

14. The meter must be protected from pressure surges.

OMNI Installation 8

Signal Connections 3DescriptionThe OMNI registers utilize fully solid-state electronics.

The OMNI C2/F2/T2 register outputs a programmable (using Sensus Unipro and OMNI communicators) digital pulse signal suited for interfacing with ACT-PAK instruments and SCADA systems to achieve a 4 to 20 mA output.

The OMNI R2 register outputs a programmable (using a Sensus Unipro communicator) register ID and AMR reading digits.

FeaturesThe OMNI register features programmable totalizer registration, digital pulse signal

(C2/F2/T2 only), AMR reading digits, and a resettable test totalizer. Because the register is hermetically sealed, it is safe for pit environments as well as above ground settings. The tamper-proof security cover can be positioned in any of 270 degrees of rotation, with indexing points at each of the 90-degree customary register viewing positions.

ApplicationThe OMNI register is used where critically accurate totalization of water is imperative. The OMNI register is designed for a non-explosive atmosphere and can be used in both above ground and pit settings. In pit settings, OMNI meters can be installed in up to 4 feet of water depth for continuous submersion and up to 10 feet for intermittent submersion.

Electrical ConnectionsThe OMNI C2/F2/T2 register is standard with both AMR and pulse output wires. The

OMNI R2 register has standard AMR wires. The pulse wire is 25 feet long; the AMR wire with touch button is 20 feet long. Splicing of these wires or connecting to these wires should be performed in accordance with standard practices depending on the environment of the application. Care must always be taken when connections are made for meters in high humidity/flooded pit settings. Maximum pulse cable length should be 1000 feet without a repeater.

The OMNI register can be configured in four arrangements, shown in the following illustrations.

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12-24 VDC

R G B

Electronic Switch(MOSFET) OMNI

Register

+Signal to

12-24 VAC Relay

Illustration 1

Illustration 1 is used when the OMNI is connected to a PLC (e.g., in a SCADA system). The PLC should not have an internal pull-up resistor in its input circuit (no DC voltage at the instrument inputs). Usually the instrument must be isolated by having an optical isolator at its inputs.

Illustration 2

Illustration 2 is used for all instruments with internal pull-up resistors. The voltage supplied by the instrument’s input when not connected to any circuitry should not exceed 24 Vdc nom. and must not exceed 30 Vdc max. Otherwise, it will overload the MOSFET inside the OMNI register. The voltage supplied to the register is allowed to be different from the instrument’s supply voltage.

Ground is common for both the OMNI register and instrument.

24 VDC

R G B


Register

+Signal to Instrument,

Supplied from Instrument/4 - 24 VDC

Ground to Instrument(if required)

Signal Connections 10

Illustration 3

Illustration 3 is used for instruments without internal pull-up resistors and without optical isolators internal to their inputs. Ground is common for both the OMNI register and instrument. When the OMNI’s MOSFET is open (not conductive), nearly the full voltage supplied to the OMNI will occur at the instrument’s input. It must be able to withstand this voltage (24 VDC in Illustration 3).

*In case the instrument’s input provides optical isolation, the connection shown in Illustration 1 should be used.

12-24 VDC

R G B


Register

+Signal to Instrumentby Pull-Up Resistor

6000 OhmResistor



Illustration 4

The table and formula are valid under the assumption that the instrument’s input resistance is higher than 50 kOhms. Otherwise, Vinstrument will be lower than shown in the table or calculated with the formula.

*If possible, the circuit of Illustration 2 should be used.

R1 R2 Vinstrument

2k 2k Vsupply/2

2k 1k Vsupply/3

6.8k 1k ~Vsupply/8

Vsupply12-24 VDC

R G B


Register

+Signal to Instrument

Vinstrument

R1 R2


VinstrumentR2

R1 R2+-------------------- Vsupply=


Measuring Chamber 4This section describes how to remove the measuring chamber and how to disassemble the measuring chamber when required to do so.

Tools Required• 2.5, 3, and 6mm hex head ball end drivers (6mm not needed for the R2)• Sensus seal screw tool—for bonnet removal• Open end/box wrenches as determined by size and type of OMNI meter

• 7/16”x1/2” open end/box wrench• 9/16” x 5/8” open end/box wrench• 3/4” x 11/16” open end/box wrench• 15/16” open end/ box wrench

• Assembly grease

CAUTION: If the meter is under pressure, pressure must be turned off and relieved before chamber bolts are loosened or removed!

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Remove the Measuring Chamber

1. With the service line pressure off, loosen all chamber cover bolts.

2. Continue loosening the bolts until all bolts and washers can be removed.

3. Use a medium-size screwdriver to pry between the valve body and chamber cover at the upstream cover bolt seal wire rib until the cover raises out of the body.

4. Remove the measuring chamber and place the chamber cover O-ring in a safe, clean place.

Chamber CoverBolts

Chamber CoverBolt Washers

Chamber CoverO-Ring

Chamber Cover

Measuring Chamber

Note: Chamber Bolt quantity varies by meter size.

(Black nylon washers are below the stainless steel washers).

Measuring Chamber 14

Disassemble the Measuring Chamber

For C2/F2/T2:

Probe Retaining Nut


For R2:

Probe Retaining Nut


1. Remove the bonnet seal screw (4) using the Sensus seal removal tool.

2. Twist the bonnet (3) counter-clockwise and lift it off the base.

3. Raise the register (5) off the base, taking care to not strain the pick-up probe wire.

4. Using your fingers (or a 7/16” wrench, if required), remove the probe retaining nut* and remove the register and probe assembly from the measuring insert. (13).

NOTE: If the pipe pressure is not yet relieved, water will spray out when the retaining nut is two turns from complete. removal.When re-installing, use fingers only and check for leaks before installing the bonnet.

5. Place the register assembly in a safe place.

6. Remove the bonnet retaining ring (7) by removing the four allen head countersink screws (6).

7. Remove the four allen head screws (14) from the measuring insert (13).

8. Pull the measuring insert (13) away from the chamber cover (11).

9. Twist the inlet flow straightener balance plate (17) counter-clockwise, then pull it straight out of the measuring insert housing.

NOTE: Take care to slowly separate the two housings or the rotor will fall out of the measuring insert and will be damaged.Do not remove the chamber seal gasket (11). It is factory glued in place for ease of chamber installation. If a replacement gasket is required, you must use a waterproof glue to attach it to the chamber.

10. .Remove the rotor (16) from the measuring insert by slowly pulling it out of the housing.

11. Inspect and replace any damaged parts.

12. For re-assembly, reverse this procedure.

Exchange the Measuring Insert• Before the installation of a replacement measuring insert, the inside surface of the

body, especially the seating areas of the O-ring, must be checked for damage. If damaged, a new O-ring must be used.

• The O-ring and the lip seal must be lubricated with grease approved for use with potable water before installation in to the meter body.

• To avoid damaging the O-ring when installing a meter insert, the O-ring must first be fitted onto the cover flange and then pushed into the meter body. If the O-ring is fitted into the body first, it can be pinched when fitting the meter inset and cause leaks.

• When installing the measuring insert into the meter body, make sure that the direction of the arrow on the head flange aligns with the arrow on the meter body.

• The screws fixing the measuring insert in the body shall be screwed hand tight and then tightened crosswise with the correct-sized tool.


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User Guide WUG-10003-02